(thio-,sulfinyl-and sulfonyl)containing pyridine compounds

ABSTRACT

THE PRESENT DISCLOSURE IS DIRECTED TO (THIO-,SULFINYL- AND SULFONYL) CONTAINING PYRIDINE COMPOUNDS CORRESPONDING TO THE FORMULA   (Q-R)M,ZP,XN-PYRIDINE   WHEREIN R REPRESENTS HYDROGEN, ALKYL MONOHALOLOWERALKYL, ALKENYL, MONOHALOALKENYL, CYCLOALKYL, MONOHALOCYCLOALKYL, PHENYL, ARALKYL, ALKARYL OR MONOHALOPHENYL, Q REPRESENTS SULFIDE (-S-), SULFINYL   -SO-, OR SULFONYL -SO2-   EACH X INDEPENDENTLY REPRESENTS CHLORINE, BROMINE OR FLUORINE, Z REPRESENTS ONE OF CYANO (-CN), CARBAMOYL (-CONH2) OF CARBOXY (-COOH) OR THE SALTS THEREOF, N REPRESENTS AN INTEGER OF 0 TO 3, INCLUSIVE, M REPRESENTS AN INTEGER OF 1 TO 3, INCLUSIVE, P REPRESENTS AN INTEGER OF 1 OR 2 AND THE SUM OF N+M+P EQUALS AN INTEGER OF 2 TO 5, INCLUSIVE, WITH THE PROVISO THAT WHEN Q IS OTHER THAN SULFIDE (-S-), R IS OTHER THAN HYDROGEN AND WHEN R IS H, M IS NOT GREATER THAN 2. THE PREPARATION OF THESE COMPOUNDS AND THEIR UTILITY AS PESTICIDES IS ALSO TAUGHT.

United States Patent 3,732,234 Patented May 8, 1973 US. Cl. 260-2943 F 7Claims ABSTRACT OF THE DISCLOSURE The present disclosure is directed to(thio-, sulfinyland sulfonyl) containing pyridine compoundscorresponding to the formula wherein R represents hydrogen, alkylmonohaloloweralkyl, alkenyl, monohaloalkenyl, cycloalkyl,monohalocycloalkyl, phenyl, aralkyl, alkaryl or .monohalophenyl; Qrepresents sulfide (-S), sulfinyl X11 Zn each X independently representschlorine, bromine or fluorine; Z represents one of cyano (CN), carbamoyl(-CONH of carboxy C'OOH) or the salts thereof; it represents an integerof to 3, inclusive; m represents an integer of 1 to 3, inclusive; prepresents an integer of 1 or 2 and the sum of n+m+p equals an integerof 2 to 5, inclusive, with the proviso that when Q is other than sulfide(S), R is other than hydrogen and when R is H, m is not greater than 2.The preparation of these compounds and their utility as pesticides isalso taught.

CROSS REFERENCE TO RELATED APPLICATION This application is a division ofmy co-pending application Ser. No. 861,506, filed Sept. 26, 1969, nowU.S. Pat. 3,639,413.

SUMMARY OF THE INVENTION The present invention is directed to (thio-,sulfinyland sulfonyl) containing pyridine compounds corresponding to theformula In this and succeeding formula, R represents hydrogen, alkyl,monohaloloweralkyl, alkenyl, monohaloalkenyl, cycloalkyl,monohalocycloalkyl, phenyl, aralkyl, alkaryl or monohalophenyl; Qrepresents sulfide (-8-), sulfinyl (-SO) or sulfonyl (-SOz) each Xindependently represents chlorine, bromine, or fluorine; Z representsone of cyano (-CN), carbamoyl (-CONH or carboxy (-COOH) or the saltsthereof; 12 represents an integer of 0 to 3, inclusive; m represents aninteger of 1 to 0.3, inclusive; p represents an integer of 1 or 2 andthe sum of n+m+p equals an integer of 2 to 5, inclusive, with theproviso that when Q is other than sulfide (S). R is other than hydrogen,and when R is H, m is not greater than 2.

Within the class of compounds described above, a preferred group ofcompounds exhibiting outstanding characteristics such as high pesticidalactivity, includes those selected from those compounds corresponding tothe formula wherein X, Q, R, n, m and p have the meanings given above.

The term alkyl as employed in the present specification and claimsdesignates a straight or branched chain alkyl radical containing from 1to 12 carbon atoms, inclusive, such as, for example, dodecyl, octyl,heptyl, hexyl, sec-hexyl, butyl, decyl, 4-methyldecyl, undecyl, nonyl,isobutyl, tert-butyl, isoamyl, amyl, propyl, ethyl, isopropyl, 3-ethylnonyl, 2-ethylhexyl, and 3-propylheptyl. The term cycloalkyl asemployed designates a cycloalkyl radical containing from 3 to 6 carbonatoms, such as, for example, cyclopropyl, cyclobutyl, cyclopentyl andcycloheXyl.

The expression loweralkyl is employed in the present specification andclaims to designate a straight or branched chain alkyl radicalcontaining from 1 to 5 carbon atoms, inclusive, such as, for example,methyl, ethyl, isopropyl, propyl, 1,l-dimethyl propyl, tert-butyl,butyl, amyl, secamyl, etc.

The term alkenyl as employed in the present specification and claimsdesignates an alkenyl radical containing from 2 to 12 carbon atoms,inclusive, such as, for example, vinyl, propenyl, Z-methyl propen-yl,butenyl, hexenyl, decenyl and dodecenyl.

The term halogen and halo are employed herein to represent chlorine,fluorine and bromine.

The term alkaryl as employed in the present specification and claimsdesignates an alkaryl radical of 7 to 9 carbon atoms, inclusicve, suchas, for example, tolyl, xylyl, ethyl phenyl or propyl phenyl.

The term salt as employed in the present specification and claimsdesignates an aralkyl radical of 7 to 9 carbon atoms, inclusive, suchas, for example, benzyl, phenethyl and phenyl propyl.

The term salt as employed in the present specifica tion and claimsdesignates the reaction products of basic compounds with the acidfunctional group COOH. Such salts can be represented by the formula--COOMe wherein Me represents ammonium, the alkali metals such assodium, lithium, potassium, cesium or rubidium, the alkaline earthmetals such as calcium, barium and strontium and the heavy metalsincluding antimony, zinc, bismuth, cad mium, cerium, chromium, cobalt,copper and other metals having a density of above 4.

For convenience, those compounds of the present invention wherein Qrepresents the sulfide group (--S) and R is hydrogen are identified asmercaptopyridines and those wherein Q is (-S-) and R is other thanhydrogen are identified as substituted thiopyridine's; those compoundswherein Q represents the sulfinyl group are identified assulfinylpyridines and those compounds wherein Q represents the sulfonylgroup are identified as sulfonylpyridines.

The pyridines of the present invention are crystalline solids or oilswhich are of low solubility in water and of moderate solubility incommon organic solvents. These compounds have low phytotoxity and aresuitable for use as pesticides in the control of various pests includinginsects and bacteria. These compounds also have low acute oral toxicityfor mammals.

The compounds of the present invention are prepared by a variety ofmethods. The mercaptopyridines, i.e., when QR is SH and Z is eithercyano, carboxy or carbamoyl can be prepared by the reaction of sodiumsulfide with an appropriate halocyanopyridine, halocarboxypyridine orhalocarbamoylpyridine in the presence of an inert solvent, followed byacidifying the reaction product. These reactions can be represented asfollows:

Reaction II Reaction I proceeds readily under ambient atmosphericpressure at temperatures of from about minus 50 to about 100 C. The tworeactants are intimately contacted in an inert solvent such as methanol,isopropanol, triethylamine, dimethoxyethane or the like. The reactionconsumes the reactants in a ratio of 1 or 2 moles of the sodium sulfideper mole of the halopyridine, depending upon whether the monoorbismercaptopyridine is the desired product. It is preferred, however,that a slight excess of the sodium sulfide be employed.

The reactants are usually mixed at a low temperature, such as aboutminus C. and the heat of reaction is allowed to raise the temperature ofthe reactants (with control) to between about 20 C. and the refluxingtemperature of the mixture. Depending on the rate of reaction, thereaction mixture may be refluxed for a period of time up to about onehour. With some reactants, the rate of reaction is so rapid as to needno refluxing. The reaction time depends on the reactants employed and isusually between about one minute and about one hour. The solvent isordinarily removed from the reaction mixture by vacuum distillation andthe residue (the sodium mercapto salt) is mixed with water and acidifiedwith a concentrated mineral acid, such as hydrochloric acid, to convertthe sodium salt to the corresponding -SH compound. The reaction productis removed by conventional liquid-solid separatory techniques, e.g.filtration, decantation, centrifugation and the like. The reactionproduct is added to a solvent or solvent mixture such as benzene orbenzene/hexane, the solution dried and the product crystallizedtherefrom. The so dried and crystallized prodnot can be employed as suchor further purified by recrystallization from an inert organic solventsuch as benzene, hexane or the like.

The thiopyridines wherein Z is either cyano, carboxy or carbamoyl and Ris an unhalogenated hydrocarbyl group, can be prepared by employing anappropriate sodium mercaptopyridine as a starting material. This lattercompound in its preparative mixture', or after separation therefrom, ismixed with an inert organic solvent and contacted with an alkyloralkenyliodide or other reactive alkylor alkenylhalide and the mixturerefluxed to prepare the final product. This reaction can be representedas follows:

( )m (in RI 7! s W X m(tIaI) Reaction III The reaction proceeds readilyunder ambient atmospheric pressure at temperatures of from about minus10 to about C. The reactants are intimately contacted in one of theinert solvents disclosed hereinbefore in the ratio of about 1 or 2 molesof the halide per mole of sodium mercaptopyridine depending on thenumber of SNa groups to be reacted to form the desired product. Thereactants are usually mixed at a low temperature which may be as low asminus 20 C. and by controlling the heat of reaction, the temperature ofthe reactants is raised to between 20 C. and the reflux temperature ofthe mixture. Depending on the rate of reaction, the reaction mixture maybe refluxed for a period of time up to about four hours. With somereactants, the rate of reaction is so rapid as to need no refluxing. Therequired reaction time is usually between about one minute and aboutfour hours. The reaction mixture is allowed to cool, diluted with waterand the resulting precipitate filtered out, dried and crystallized in aconventional manner.

An alternative procedure for preparing the above alkyl thiopyridinesinvolves the direct reaction of a polyhalopyridine, sodium metal and theappropriate mercaptan in the presence of an organic solvent of a typeconventionally used for such reactions. This reaction can be representedas follows:

Reaction IV The reaction is carried out by dissolving the sodium metalin a cold organic solvent such as methanol. The mercaptan is added tothis cold solution, with stirring, and the resulting mixture is slowlyadded to the halopyridine also dissolved in methanol. This mixture isrefluxed for a time sufficient to complete the reaction, usually fromabout one to about three hours. The reaction products are filtered toremove any sodium halide, followed by solvent removal by evaporation,distillation or other conventional separatory procedures. The residue isconveniently taken up in a warm solvent mixture, i.e. a benzene-hexanemixture, to remove any remaining sodium halide and then cooled torecrystallize the product, which may be separated by a conventionalseparatory procedure. Again, as in the above described preparationprocedures, the reaction consumes the reactants in a ratio of about 1 or2 molecular or atomic proportions of the mercaptan and sodium metal permole of halopyridine, depending on whether the mono-, orbisthiohalopyridine is the desired product and the use of these ratiosis preferred. The reaction conditions are also the same as hereinbeforeset forth.

In an alternative procedure for preparing monohaloloweralkylandmonohalocycloalkyl thiopyridines, a monomercaptohalopyridine is reactedwith a halogen (chlorine or bromine) in carbon tetrachloride to convertthe mercaptohalopyridine to the corresponding sulfenyl halide (SX) whichis in turn adducted with the alkenyl group of an alkene or cycloalkeneto form the final alpha halosulfide product. Representative examples ofsuch unsaturated compounds include ethylene, propylene, n-butylene,isobutylene, amylene, and cyclohexene. These reactions can berepresented or exemplified as follows:

X" C X H6].

z )9 l )p Emotion V C1 H I set 'g H H x uc ca n Reaction VI The reactionconditions and times are generally the same as for the hereinbeforedescribed procedures. The reaction consumes the reactants in a ratio of1 mole of the unsaturated compound per mole of the halopyridyl sulfenylhalide.

When the bisor tris(haloloweralkylor halocycloalkylthiolpyridine is thedesired product, each additional haloloweralkyl or halocycloalkylthiogroup must be added separately. In such a procedure, the abovemonothiohalopyridine product is reacted with sodium sulfide followingthe procedures of Reactions I and II to prepare a product containing anadditional mercapto group. The product is reacted with a halogen(following the procedure of Reaction V) to convert the mercapto group tothe sulfenyl halide which may then be adducted with an additional alkeneor cycloalkene (following the procedures of Reaction VI) to prepare thebis- (haloloweralkylthio) or (halocycloalkylthio)pyridine. The abovesteps are repeated when the tris compound is the desired product. Thealkene or cycloalkene compound employed in a second or third aductionstep does not have to be the same as that employed in a prior adductionstep.

The ammonia, alkali metal, alkaline earth metal and heavy metals saltsof the present invention are prepared by conventional technique wherebythe carboxyl group of a carboxy substituted alkyl nitrile is reactedwith a hydroxide, oxide, carbonate or bicarbonate of one of the abovegrouped metals. They can in some cases also be made by direct reactionwith the metals.

The mono-, bisor trissulfinyland sulfonyl-halopyridine counterparts ofthe present invention are prepared by reacting the appropriate mono-,bis-, or tristhiohalopyridine with an oxidizing agent. The oxidation ofany of the thiohalopyridines of this invention results, at leastpartially, in the formation of the corresponding sulfinylhalopyridinecompound.

The oxidation of one molecular of the thiohalopyridine to thecorresponding sulfinylhalopyridine or the oxiadtion of one molecule of asulfinylhalopyridine to the corresponding sulfonylhalopyridine requiresone atom of oxygen for each sulfur atom oxidized. The oxidation of thethiohalopyridines directly to the corresponding sulfonylhalopyridine, onthe other hand, consumes two atoms of oxygen for each sulfur atom ineach molecule of thiohalopyridine so oxidized.

In carrying out the various oxidation reactions to prepare the sulfonylcompounds of the present invention, it is preferable to employ an excessof the oxidizing agent, whereas in preparing the sulfinyl compounds, itis preferable not to provide oxygen appreciably in excess of thestoichiometric quantities consumed in the conversion and to employmilder reaction conditions and/ or oxidants.

In many instances, the sulfinylpyridine can be prepared and subjected tocontinuing oxidative conditions so as to be further oxidized in situ tothe corresponding sulfonylhalopyridine compound. In some instances,depending on the oxidizing agent and process conditions, the oxidationproceeds to the sulfonylhalopyridine so rapidly that it is not practicalto isolate the sulfinyl compound. Representative oxidizing agents forthe production of the sulfinylhalopyridine compounds include nitric acidand hydrogen peroxide and representative oxidizing agents to be employedin the preparation of the sulfonyl compounds include hydrogen peroxide,and perbenzoic acid.

Hydrogen peroxide, and conveniently an aqueous solu tion thereof, can beemployed as the oxidizing agent in the production of the sulfinyl andsulfonyl pyridine derivatives of the present invention. In suchembodiment, the reaction is carried out in the presence of a liquidreaction medium, such as trifiuoroacetic acid, glacial acetic acid or amixture of acetic acid and acetic anhydride. In a preferred procedure,the acid-anhydride mixture is employed as the liquid reaction medium.The reaction takes place at temperatures of from about to about 120 C.In a convenient method, the reaction is carried out at the boilingtemperature of the reaction mixture and under reflux. In carrying outthe reaction, the reactants are contracted in any order or fashion, andpreferably in amounts stoichiometric for the preparation of the desiredproduct. The reaction mixture is then maintained at a temperature withinthe reaction temperature range until the desired degree of conversion isachieved. Following the reaction period, the mono-, bisortrissulfonylpyridine product can be separated by conventional proceduressuch as evaporation of the reaction medium to obtain the product as asolid residue. In an alternative procedure, the reaction mixture iswashed with cold water and is thereafter filtered, centrifuged or thelike to obtain the crystalline product.

Nitric acid is conveniently employed to oxidize the mono-, bisortristhiopyridine starting materials to the corresponding mono-, bisortrissulfinylpyridines. The reaction can be carried out in the presenceof a halocarbon reaction medium such as carbon tetrachloride, methylenedichloride, ethylene dibromide, etc. In a preferred procedure, excessnitric acid is employed as the reaction medium. The reaction proceeds attemperatures between about 15 C. and about 120 C. Preferably thereaction is carried out under reflux conditions at temperatures of fromC. to 120 C. and requires only a short period of time for completion,i.e., about 2 to about 7 minutes. Conveniently, the reactants are mixedand the temperature is allowed to rise to the desired temperature andmaintained at or about this temperature during the refluxmg.

The contacting of the reagents and separation and isolation of thedesired product are all as previously described.

In an additional procedure, chlorine water can also be employed as theoxidizing agent in the preparation of mono-, bisor trissulfinylorsulfonyl pyridines from the corresponding thio pyridine or sulfinylpyridines. However, the cyano groups in the compounds of this inventionare generally readily hydrolyzed and usually this oxidizing agent shouldnot be employed unless the carboxy or carbamoyl hydrolysis product ofthe cyano group is also desired. When employing chlorine water as anoxidizing agent, a slurry of the sulfide compound to be oxidized isprepared in water and the slurry agitated while chlorine gas is bubbledin. The mixture is maintained at room temperature until no startingsulfide material is left unoxidized. If it is desired to convert thesulfinyl compound to the sulfonyl state, the temperature is raised toabout C. and the mixture maintained at this temperature until oxidationis complete. This mode of oxidation is further discussed in US. Pat.3,415,832.

The monohaloalkenylthio pyridines can be prepared by adducting asulfenylhalide as hereinbefore prepared (Reaction V) with an acetyleniccompound under the conditions set forth for Reaction VI. Representativeacetylenic compounds include, for example, acetylene, ethyl acetylene,n-propylacetylene, l-hexyne, n-amyl acetylene, 5- methyl 1 hexyne,l-octyne, di-n-propylacetylene, di-tbutylacetylene.

The oxidation of the halosulfide product to the sulfinyl or sulfonylproduct is quite diflicult and these compounds can be prepared byconventional dehydrohalogenation of a dihalosulfinylor sulfonylpyridinewith an organic base such as, for example, trimethylamine.Dihalosulfinylor sulfonyl compounds having utilities of the types taughtherein are prepared by adducting a sulfenyl halide with amonohaloalkenyl compound employing the conditions of Reaction VI.Representative of such monohaloalkenes include, for example, allylbromide, allyl iodide, -brom0-2- pentene, 4-bromo-1-butene,4-bromo-1-hexene, l-chloro- 4 octene, 7 bromo-l-decene and4-brorno-3-methyl-2- butene.

DESCRIPTION OF SOME PREFERRED EMBODIMENTS The following examplesillustrate the present invention and the manner by which it can bepracticed but, as such, should not be construed as limitations upon theoverall scope of the same.

EXAMPLE 1 3,5,6-trichloro-4-mercapto-2-cyanopyridine A solution isprepared containing 20 grams (0.08 mole) of tetrachloro 2 cyanopyridineand 200 milliliters of isopropanol which is added very quickly to anagitated solution of 21.86 grams (0.09 mole) of sodium sulfidenonahydrate in 200 milliliters of isopropanol at 70 C. and the mixturerefluxed for one hour at 82 C. The isopropanol is stripped off undervacuum and the residue is diluted with water and acidified with 11.89grams of concentrated hydrochloric acid. A precipitate of3,5,6-trichloro-4-mercapto 2 cyanopyridine product is formed recoveredby filtration, dried in a benzene solution with anhydrous sodium sulfateand recrystallized from hexane. The product is recovered in a yield of92.5 percent of theoretical and has a melting point of 128 -|130 C. Theproduct is found by analysis to have carbon, hydrogen, chlorine,nitrogen and sulfur contents of 31.49, 0.73, 42.58, 11.81 and 12.98percent, respectively, as compared to the theoretical contents of 31.30,0.46, 43.60, 11.51 and 13.13 percent, respectively, calculated for thenamed structure.

EXAMPLE 2 2,5 ,6-trichloro-4-mercapto-3-cyano pyridine A solution isprepared containing 50 grams (0.21 mole) sodium sulfide nonahydratedissolved in 150 milliliters of water and this solution is quicklypoured into a solution of 50 grams (0.21 mole) oftetrachloro-3-cyanopyridine in about 300 milliliters of dimethoxy ethaneat about minus 20 C. The reaction mixture becomes a clear dark red colorand the temperature is maintained at minus C. The solution is cooled andacidified with concentrated hydrochloric acid until precipitationceases. The 2,5,6-trichloro-4-mercapto-3-cyanopyridine product isrecovered by filtration and dried in a benzene solution. The solution isdiluted with hexane and the product is recovered by recrystallizationfrom this solution. The product ,is obtained in a yield of 52.4 percentof theoretical, melts at 136 C. and is found by analysis to have carbon,hydrogen, chlorine, nitrogen and sulfur contents of 30.33, 0.75, 43.91,11.85 and 13.16 percent, respectively, as compared with the theoreticalcontents of 30.08, 0.42, 44.40, 11.72 and 13.38 percent, respectively,calculated for the named structure.

EXAMPLE 3 3,5-dichl0ro-4-mercapto-2,6-dicyanopyridine and4,5-dich1oro-3-mercapto-2,6-dicyanopyridine 01 s11 01 or NC 0 CN+ CN CNA solution is prepared by dissolving 9.0 grams (0.39 mole) of3,4,5-trichloro-2,6-dicyanopyridine in milliliters of dimethoxyethaneand this solution is quickly added, with stirring, to a cold (minus 10C.) solution of sodium sulfide nonahydrate (9.32 grams, 0.39 mole)dissolved in 70 milliliters of water. The temperature is maintainedbetween 0 and 25 C. The reaction mixture is stirred for 20 minutes andthe solids formed are filtered off. The remaining liquid is acidifiedwith concentrated hydrochloric acid until acidic to pH paper and theresulting product as a precipitate is recovered by filtration. Theproduct is subsequently analyzed by Nuclear Magnetic ResonanceTechniques and determined to be about 40 mole percent3,5-dichloro-4-mercapto-2,6- dicyanopyridine and 60 mole percent4,5-dichloro-3-mercapto-2,6-dicyanopyridine. The product is found byfurther analysis to have carbon, hydrogen, chlorine, nitrogen and sulfurcontents of 37.70, 0.50, 28.60, 18.80 and 13.44 percent, respectively,as compared with the theoretical contents of 36.50, 0.44, 30.80, 18.24and 13.90 percent, respectively, calculated for either of the namedstructures. The individual isomers are recoverable by conventionalprocedures such as, for example, preparative vapor phase chromatography,fractional crystallization and the like.

EXAMPLE 4 3 ,6-dichloro-5- (mthylthio -2,4-dicyanopyridine A solution isprepared by dissolving 4.6 grams of trichlor0-2,4-dicyanopyridinedissolved in 10 milliliters of dimethoxyethane at 50 C. and to this isadded a solution containing 4.8 grams of sodium sulfide dissolved in 10milliliters of water. The temperature is allowed to rise to 65 C. andthe reaction mixture is held at this temperature for 10 minutes andcooled to about 10 C. To this reaction mixture is added a solutioncontaining 2.9 grams (0.02 mole) of methyl iodide dissolved inmilliliters of dimethoxyethane and the reaction mixture is refluxed for30 minutes and quenched in ice water. The3,6-dich10ro-5-methylthi0-2,4-dicyanopyridine product is recovered byfiltration and consecutively recrystallized from pentane, hexane andmethyl cyclohexane. The so purified product is found to have a meltingpoint of 104-106 C.

EXAMPLE 5 3 ,4,5-tris (methylthio -2,6-dicyanopyridine 0 H3 mo s s cm Asolution is prepared by dissolving 0.36 grams (0.02 mole) of sodiumchips in 30 milliliters of methanol and cooling to a temperature of 25C. To this solution is added over a period of 15 minutes, coldmethylmercaptan in an amount of 0.82 gram (0.02 mole). The resultingmixture is added slowly to a refluxing suspension of 3,4,5- trichloro2,6 dicyanopyridine (3.65 grams, 0.02 mole) in 25 millilitersofmethanol. The reaction mixture is refluxed for three hours, filtered toremove sodium chloride formed and cooled to precipitate the3,4,5-tris-(methylthio)-2,6-dicyanopyridine product. The product isrecovered by filtration and recrysatllized from benzene. The product hasa molecular weight of 267 and the structure is confirmed by nuclearmagnetic resonance analysis.

EXAMPLE 6 3,5 ,6-trifluoro-4-(methylthio)-2-cyanopyridine s CH3 l 1 F NCN Into a 250 milliliter flask containing 30 grams (0.17

mole) of tetrafiuoro-2-cyanopyridine maintained at minus C. in a Dry Icebath, is added 9.0 grams (0.19 mole) of methylmercaptan, with stirring.Triethylamine (17.2 grams, 0.17 mole) is added dropwise while thetemperature is held at about minus 10 C. The reaction mixture is held atice bath temperature for one hour and allowed to come to ambient roomtemperature and held at this temperature for about 12 hours. Thereaction mixture is washed with water and the insoluble residue taken upwith methylene dichloride. The' solution is dried with sodium sulfate,filtered and the methylene dichloride distilled away leaving the3,5,6-trifluoro-4-(methylthio)-2- cyanopyridine product. This product, ayellow liquid, has a boiling point at 38 milliliters of mercury of138-140 C., is recovered in a yield of 73 percent of theoretical and isfound by analysis to have carbon, hydrogen, fluorine, sulfur andnitrogen contents of 41.15, 1.41, 27.80, 15.61 and 13.58 percent,respectively, as compared with the theoretical contents of 41.18, 1.48,27.92, 15.70 and 13.72 percent, respectively, calculated for the name-dstructure.

EXAMPLE 7 3,5,6'trichloro-4- (o-chlorocyclohexyl thio] -2- cyanopyridineTo a 450 milliliter solution of carbon tetrachloride saturated withchlorine (C1 is added with stirring, 20 grams (0.08 mole) of3,5,6-trichloro-4-mercapto-2-cyanopyridine (prepared as per Example 1).During this step, the mercapto group in the 3,5,6-trichloro-4-mercapto-2cyanopyridine is converted to sulfenyl chloride group. T 0 this reactionmixture is added 6.86 grams (0.08 mole) of cyclohexene and the mixturestirred for 15 minutes at ambient room temperature and filtered toremove any insoluble material. The carbon tetrachloride is removed andthe solid 3,5,6 trichloro 4-[(o-chlorocyclohexy1) thio]-2-cyanopyridineproduct remaining is recrystallised from hexane, filtered and freed ofsolvent. The product is recovered in a yield of 52.4 percent, has amelting point of 91 C. and is found to have carbon, hydrogen, chlorinenitrogen and sulfur contents of 40.60, 2.80, 40.38, 8.10 and 8.95percent, respectively, as compared with the 10 theoretical contents of40.75, 2.28, 40.0, 7.92 and 9.05 percent, respectively, calculated forthe named structure.

EXAMPLE 8 3,5,6-trichloro-4-(methylsulfinyl)-2-cyanopyridine To a flaskcontaining 50 milliliters of concentrated nitric acid at roomtemperature is added portionwise, with stirring, 10 grams (0.04 mole) of3,5,6-trichloro-4-(methylthio)-2-cyanopyridine. The temperature of themixture is quickly raised to C. The mixture is held at 85 C. for 6minutes and then quickly cooled and poured into ice water, stirred andthe resulting solid precipitate of 3, 5,6trichloro-4-(methylsulfinyl)-2-cyanopyridine-product is removed byfiltration and dried. The product is recovered in a yield of 5.87 gramsand has a melting point of 124 C.

EXAMPLE 9 2,5,6-trichloro-4-(methylsulfinyl) -3-cyanopyridine Cl ON IO N01 To an agitated solution containing 7.36 grams (0.03 mole) of2,5,6-trichloro 4-(methylthio)3-cyanopyridine, 20 milliliters of aceticacid and 20 milliliters of acetic anhydride at room temperature is addeddropwise. 13.12 grams of 30 percent hydrogen peroxide. The mixture isstirred until the temperature exothermically rises to 60 C. Thetemperature is then raised to the reflux temperature of the mixture C.)and refluxed for one half hour. Additional hydrogen peroxide is added inthe amount of 20 milliliters and the mixture is allowed to stand at roomtemperature for about 12 hours after which, the mixture is refluxed anadditional one half hour. An additional 10 milliliters of hydrogenperoxide is added and the mixture is refluxed an additional one halfhour. The reaction mixture is poured into ice water and the white solid2,5,6-trichloro-4-(methylsulfinyl)-3- cyanopyridine product precipitatesand is filtered off. The solid material is mixed with a hexane-methylenedichloride solvent mixture, heated and filtered to remove someundissolved product. The remaining liquid is cooled and filtered torecover additional product. The product is recovered in a total yield of5.5 grams and has a melting point of 179 C.

EXAMPLE 10 3,5 ,6-trichloro-4-(methylsulfonyl)-2-cyanopyridine To anagitated solution containing 4.7 grams (0.02 mole) of3,5,6-trichloro-4-(methylthio)-2cyanopyridine (prepared by the method ofExample 1) in 10 milliliters of acetic acid and 10 milliliters of aceticanhydride, is added slowly 0.84 gram of 30 percent hydrogen peroxide.The temperature is allowed to rise to 70 C., exothermically, and thereaction mixture is refluxed at 105 C. for

27 minutes. An additional 4.2 grams of hydrogen peroxide is added afterthe first 20 minutes of reflux has occurred. The reaction mixture ispoured over ice and filtered to recover the precipitated3,5,6-trichloro-4- (methylsulfonyl)-2-cyanopyridine product. The productis obtained in a yield of 57.4 percent, has a melting point of 138.5 C.and is found by analysis to have carbon, hydrogen, chlorine, nitrogen,sulfur and oxygen contents of 29.56, 0.82, 37.12, 10.01, 11.08 and 10.41percent, respectively, as compared with the theoretical contents of29.45, 1.05, 37.20, 9.83, 11.24 and 11.23 percent, respectively,calculated for the named structure.

EXAMPLE 11 3,5 ,6-tribromo-4- (methylsulfonyl -2-cyano pyridine Br Dr,cent hydrogen peroxide with stirring. The temperature is allowed torise exothermically to 45 C. and the temperature is raised to the refluxtemperature of the mixture and the mixture refluxed for 50 minutes. Thereaction mixture is cooled and poured into ice Water. To the quenchedmixture is added 5 milliliters of a concentrated solution of sodiumsulfate in water to precipitate the 3,5,6tribromo-4-(methylsulfonyl)-2-cyanopyridine product. The product isfiltered and dried in benzene with anhydrous sodium sulfate. The benzeneis removed and the resultant oil crystallized from cold methanol andfiltered to recover the solid. The product was obtained in a yield of3.31 grams, having a melting point of 148 C. and was found by analysisto have carbon, hydrogen, bromine, nitrogen, sulfur and oxygen contentsof 20.39, 0.75, 56.98, 6.84, 7.52 and 7.52 percent, respectively, ascompared with the theoretical contents of 20.08, 0.72, 5724, 6.69, 7.62and 7.65 percent, respectively, calculated for the named structure.

EXAMPLE 12 3,5,6-trichloro-4-(decylsulfonyl -2-cyanopyridine To anagitated 100 milliliter solution of acetic acid at room temperature isslowly added, 12.0 grams of 30 percent hydrogen peroxide and grams (0.03mole) of 3,5,6 trichloro 4 (decylthio)-2-cyanopyridine. After theadditions are complete, the mixture is stirred, at room temperature, forone hour and then refluxed at 109 C. for two hours. The reaction mixturetemperature is reduced to 70 C. and an additional 10 grams of hydrogenperoxide are added. The mixture is allowed to stand for about 12 hours.The mixture is refluxed at about 109 C. for 10 minutes, cooled andpoured into ice water. Saturated aqueous sodium sulfate is slowly addeduntil precipitation is complete. The solid3,5,6-trichloro-4-(decylsulfonyl)-2-cyanopyridine product is recoveredby filtration and dried in benzene with sodium sulfate. The benzene isthen removed and the residual material contacted with hexane. The solidproduct is crystallized from methanol and dried. The product has amelting point of 67.5 C. and is found by analysis to have carbon,hydrogen,

12 chlorine, nitrogen, sulfur and oxygen contents of 47.23, 5.01, 25.64,7.51, 7.66 and 6.95 percent, respectively, as compared with thetheoretical contents of 46.60, 5.13, 25.90, 6.81, 7.80 and 7.76 percent,respectively, calculated for the named structure.

EXAMPLE 13 2,5-dichloro-4,6-bis [(p-chlorophenyDsulfonyl1-3-cyanopyridine To an agitated solution containing 7.56 grams (0.02 mole)of 2,5 dichloro 4,6 bis[(p-chlorophenyl)thio]- 3-cyanopyridine, 30milliliters of acetic acid and 15 milliliters of acetic anhydride atroom temperature is added 9.75 grams of 30 percent hydrogen peroxide.The temperature is allowed to exothermically rise to C. and the mixtureheated at its reflux temperature for one half hour. An additional 80milliliters of acetic acid and 15 milliliters of acetic anhydride areadded followed by an additional 6 milliliters of hydrogen peroxide. Themixture is refluxed for one half hour, cooled and added to ice water andthe solid 2,5-dichloro-4,6-'bis[(p-chlorophenyl)sulfonyl]-3-cyanopyridine product is recovered by filtration and dried.The product is recovered in a yield of 4.2 grams having a melting pointof 227 C. and is found by analysis to have carbon, hydrogen, chlorine,nitrogen and sulfur contents of 41.90, 1.60, 27.12, 5.70, 12.14 and11.54 percent, respectively, as compared with the theoretical contentsof 41.40, 1.50, 27.18, 5.37, 12.28 and 12.27 percent, respectively,calculated for the above named structure.

EXAMPLE 14 3,5,6-trichloro 4-(methylthio)-2-carboxypyridine soul or 0 oror ooorr A solution is prepared by dissolving .874 gram (0.02 mole) ofsodium chips in milliliters of methanol. The solution is cooled to 0 C.and 2.2 grams (0.02 mole) of methyl mercaptan is added with agitation.This solution is added slowly to a refluxing solution of 5.0 grams (0.01mole) of tetrachloropicolinic acid in 25 milliliters of methanol andrefluxed at C. for 3 hours. To this reaction mixture is added 50milliliters of water to dissolve the precipitated sodium chloride andthe mixture carefully acidified with hydrochloric acid until the solidcrude 3,5,6 trichloro 4 methylthio-2-carboxypyridine product iscompletely precipitated. The solid is dried by aspiration and taken upin benzene and dried with sodium sulfate. The benzene is partiallyremoved and the product recrystallized from a benzene-hexane mixture.The 3,5,6- trichloro 4 (methylthio) 2 carboxypyridine product has amelting point of 119 C., is recovered in a yield of 99.8 percent oftheoretical (5.16 grams) and is found to have carbon, hydrogen,chlorine, nitrogen, oxygen and sulfur contents of 31.02, 1.44, 39.28,4.93, 11.77 and 11.56 percent, respectively, as compared with thetheoretical contents of 30.85, 1.46, 39.05, 5.14, 11.74 and 11.76percent, respectively, calculated for the named structure.

The following compounds of the present invention are prepared inaccordance with the methods herein set forth. (M.P., B.P. and M.W.designated melting point, normal boiling point and molecular weight,respectively.)

2,5,6-trichloro-3-(methylthio)-4-cyanopyridine,

3 ,5 ,6-trichloro-4- (methylthio) -2-cyanopyridine,

M.P. 58 C. 3 ,4,5-trichloro-6- (methylsulfonyl) -2-cyano pyridine,

M.P. 157.5 C. 3 ,5 ,6-trifluoro-4- (methylsulfonyl -2-cyanopyridine,

M.P. 75-77 C. 3,5,6-tribromo-4-(methylthio)-2-cyanopyridine,

B.P. 112 C. 3,5 ,6-trichloro-4- propylsulfonyl) -2- cyano pyridine,

M.P. 166 C. 3,5 ,6-trichlo1'0-4- propylthio) -2-cyanopyridine,

M.W. 281.54 3,5 ,6trichlro-4- (o-chlorocyclohexyl sulf0nyl1-2-cyanopyridine, M.P. 189190 C.3,5dichloro-4,6-bis(methylthio)-2-cyanopyridine,

M.P. 57 C. 2,3,5-trichloro-6-(propylsulfonyl)-4-cyanopyridine,

M.P. 137 C. 3,5,6-trichloro-4-mercapto-2-carbamoylpyridine,

M.P. 182 C. 3,5,6-trichloro-4-mercapto-2-carboxypyridine,

M.P. 186 C. 3,5-dichloro-4- (methylthio) -2,6-dicyanopyridine,

M.P. 63-66 C. 3,4-dichloro-- (methylthio) -2,6-dicyanopyridine,

M.P. 63-66 C. 3,6-dichloro-5-(propylthio)-2,4-dicyanopyridine,

M.P. 48-50 C. 3,5,6-trichloro-4-(methylsulfonyl)-2-carboxypyridine,

M.W. 306.52 3 ,5 ,6-trichloro-2- methylsulfonyl) -4-carb amoylpyridine,

M.P. 211.5 C. 2,5,6-trichloro-3-(methylsulfinyl)-4-carboxypyridinesodiumsalt. M.W. 308.50 3,5,6-trichloro-2-(methylsulfonyl)-4-carboxypyridine,

M.P. 196 C. 2,5,6-trichloro-3-(methylsulfinyl)-4-carboxypyridine,

M.P. 206-209 C. 3,5,6-trichloro-4-(methylsulfinyl)-4-cyanopyridine,

M.W. 379.61, 90.5 percent yield3,5,6-trichloro-2-(methylsulfinyl)-4-carboxypyridinechromium salt, M.W.355.52 2,5,6-trichloro-4-(methylsulfinyl)-3-cyanopyridine,

M.P. 179 C. 2,3,6-trichloro-5-(propylsulfonyl)-4-cyanopyridine, M.P.

110112 C. 3,5-difluoro-4,6-bis(propylthio)-2-cyanopyridine, M.W.

288.37 3 ,5-difiuoro-4, 6-bis (propylsulfonyl) -2-cyanopyridine,

M.P. 183-186 C. 2,4,6-trichloro-5-(methylthio)-3-cyanopyridine, M.W.

253.52 2,5,6-trichloro-4-(vinylthio)-3-cyanopyridine, M.W.

265.53 2,5,6-trichloro-4-(methylthio)-3-cyanopyridine, M.W.

253.52 3,5-dichloro-4- (propylthio -6-(ethylthio) -2-cyanopyridine, M.W.307.17 2,4,6-trichloro-5- (methylsulfonyl)-3-cyanopyridine, M.W.

285.54 2,5 ,6-trichloro-4- methylsulfonyl) -3 -cyano pyridine,

M.W. 285.54 2,5, 6-trichloro-4- (phenethylthio -3 -carb oxypyridine,

M.W. 362.48 2,5,6-trichloro-4- (p-chlorophenyl thio] -3-cyanopyridine,

M.W. 350.03 2,4,6-trichloro-5-[ (p-chlorophenyl thio] -3-cyanopyridine,

M.W. 350.03 2,5-dichloro-4,6-bis(p-chloropheny1)thio]-3-cyanopyridine,M.W. 458.16 3,5,6-trichloro-4-mercapto-2-carboxypyridine-calcium salt,M.W. 296.59 3,5,6-tribromo-4-(3-ethylphenylsulfonyl)-2-carboxypyridine,M.W. 527.86

3,4,5-trichloro-6-(phenylpropylthio)-2-carbamoxypyridine M.W. 359.59

3,4,5-trichloro-6- (methylthio -2-cyanopyridine, M.W.

2,5,6-trichloro-3-(methylsulfonyl)-4-cyanopyridine, M.P.

2,5,6-trichloro-3-(benzylsulfinyl)-4-cyanopyridine, M.W.

2,5,6-trichloro-3- (propylsulfonyl)-4-cyanopyridine, M.W.

3-bromo-S,6-dichloro-2-(ethylsulfonyl)-4-carboxypyridine, M.W. 363.09

2,6-dichloro-5-bromo-3-(methylthio)-4-cyanopyridine,

3-ch1oro-5 -bromo-4- methylsulfinyl -2,6-dicyanopyridine,

2,3,5-trichloro-6-(methylsulfonyl)-4-cyanopyridine, M.P.

2,5-dichloro-3-(benzylsulfinyl)-6-(propylsulfinyD-4- cyanopyridine, M.W.369.14

3,5 -dichloro-4- methylsulfonyl) -2,6-dicarboxylpyridine,

3,S-dichloro-S-(methylsulfonyD-Z,4-dicarbamoylpyridine, M.W. 312.07

3,5,6-trichloro-2-(propylthio)-4-cyanopyridine, M.W.

3,5-dichloro-6- (methylsulfonyl) -2,4-dicyanopyridine,

3,6-dichloro-5- (methylsulfonyl) -2,4-dicyanopyridine,

M.P. 208-214 C.

3,5, 6-trichloro-4- (dodecylsulfonyl -2-cyanopyridine,

2,3,6-trichloro-5-mercapto-4-cyanopyridine, M.P. 100 C.

2,3 ,6-trichloro-5- 3-propylphenylthio) -4-cyanopyridine,

In accordance with the present invention, it has been discovered thatthe mono-, bisor tristhio-, sulfinyl and sulfonyl pyridine compounds canbe employed as pesticides for the control of many bacterial, fungal andinsect pests. In still further operations, the compounds of theinvention or compositions containing them as toxic constituents can beincluded in and on plaster, ink, wallboard, textiles, paper, adhesives,soaps, synthetic detergents, cutting oils, polymeric materials,embalming fluids, oil paints and latex paints to prevent the attack ofvarious fungal pests and the subsequent economic loss due to thedegradation of such products by microorganisms. Also the compounds canbe distributed in textiles or cellulosic materials to preserve andprotect such products from the attack ot the organisms of rot, mold anddecay. They also can be employed as a toxicant to control insect pests.

The exact concentration of the toxicant to be employed in the treatingcompositions is not critical and may vary considerably provided therequired dosage of the elfective agent is supplied in the ink, adhesive,soap, cutting oil, polymeric material, paint, textile, paper, or growthmedium or when employed to contact insects. The concentration oftoxicant in liquid compositions generally is from about 0.0001 to 50percent by weight. Concentrations up to percent by weight are oftentimesconveniently employed, particularly in concentrate compositions. Industs, the concentrations of the toxicant can be from about 0.1 to 95percent by weight. In compositions to be employed as concentrates, thetoxicants can be present in a concentration of from 5 to 98 percent byweight. For use as a spray, it is often convenient to apply thecompounds as wettable powders.

In a representative operation, each of the compounds 2,3 ,5-trichloro-6- methylsulfonyl -4-cyanopyridine, 3,5 ,6-trichloro-4-methylsulfonyl -2-cyanopyridine, 2,3,5 -trichloro-6- propylsulfonyl)-4-cyanopyridine, 3,5 -diflu0ro-4,6-bis propylsulfonyl -2-cyanopyridine,3 5,6-tritluoro-4- (methylsulfonyl -2-cyanopyridine, 2,5 ,6-trichloro-4-(methylsulfinyl) -3-cyanopyridine,

1 3,5 ,6-trifluoro-4-(methylthio)-2-cyanopyridine, 2,3,6-trichloro-5-(propylsulfonyl)-4-cyanopyridine, 3,5,6-trichloro-4-(decylsulfonyl)-2-cyanopyridine, 3 ,5 ,6-trichloro-4-propylsulfonyl) -2-cyanopyridine and 3,5,6-trichloro-4-mercapto-2-cyanopyridine when employed as the soletoxicant in a nutrient agar at a concentration of about 500 parts byweight of the compound per million parts of agar is found to give 100percent kill and control of the organisms Staphylococcus aureus andBacillus subtilis.

In another representative operation, employing the same nutrient agarand toxicant concentration, 3,5,6-trichloro- 4-mercapto 2carboxypyridine and 3,5,6-trichloro-4- (methylthio-3)-2-carboxypyridineare found to give 100 percent kill and control of the organism Bacillussubtilis and Salmonella typlzosa; 3,5,6 trichloro-4-mercapto-2-carbamoylpyridine is found to give 100 percent kill and control ofBacillus subtilis and Mycobacterium phlei and 3,5 ,6-trichloro-4-(methylsnlfonyl) 2 carboxypyridine and 3,5-dichloro-4,6bis(methylthio)-2-cyanopyridin are found to give i100 percent kill andcontrol of T richophyton mcntagrophytes.

In additional operations employing the same toxicant concentration andnutrient agar, each of the compounds 2, 3 ,5 -trichloro-6-(methylsulfonyl) -4-cyanopyridine,2,5,6-trichloro-4-(methylsulfinyl)-3-cyanopyridine, 3,5,6-trichloro-4-(methylsulfonyl)-2-cyanopyridine,2,3,4-trichloro-6-(propylsulfonyl)-4-cyanopyridine, 3,5,6-trifluoro-4-(methylthio)-2-cyanopyridine,2,3,6-trichloro-5-(propylsulfonyl -4-cyanopyridine, 3 ,5 ,6-trichloro-4-propylsulfonyl -2-cyanopyridine,3,5,6-tribromo-4-(methylthio)-2-cyanopyridine and3,5,6-trichloro4-mercapto-2-cyanopyridine give 100 percent kill andcontrol of the organisms Candida albicafls, Candida pellicu losa,Pullularia pullulans and Aspergillus terreus.

In another representative operation employing the same toxicantconcentrations and agar, each of the compounds2,3,5-trichloro-6-(methylsulfonyl)-4-cyanopyridine,2,5,6-trichloro4-(methylsulfinyl)-3-cyanopyridine,3,5,6-trichloro-4-(methylsulfonyl)-2-cyanopyridine,2,3,5-trichloro-6-(propylsulfonyl)-4-cyanopyridine,3,5,6-trifluoro-4-(methylthio)-2-cyanopyridine, 2,3,6-trichloro-5-(propylsulfonyl)-4-cyanopyridine and 3,5,6trichloro-4-(propylsulfonyl)-2-cyanopyridine give 100 percent kill andcontrol of the organisms Rhizopus nigricans, Mycobacterium phlei andTriclwphyron mentagrophyt s.

In an additional operation employing the same toxicant concentration andnutrient agar, 2,5,6-trichloro-3-(methylsulfinyl)-4-carboxypyridine isfound to give 100 percent kill and control of the organisms Candidaalbicans, Triclzophyton menragro lzytes and Mycobacterium phlei;2,5,6-trichloro-4-(methylsulfinyl) 3 cyanopyridine is found to give 100percent kill and control of Psuedomonas aeruginosa, Escherichia coli,Aerobacter aer genes and Salmonella typ/zosa; 3,5,6-trichloro 4(propylthio)-2- cyanopyridine gives 100 percent kill and control ofTriclzophyt n mentagrophytes, Pullularia pullulans and Mycobacteriumphlei; each of 3,5,6-trichloro-4-(decylsulfonyl -2-cyanopyridine and 3,5,6-tribromo-4- (methylthio)-2-cyanopyridine is found to give 100 percentkill and control of Cephaloascus fragans, Triclzoplzyton m ntagrophytesand Mycobacterium phlci and 3,5-dichloro-4,6-bis(methylthio) is found togive 100 percent kill and control of Rhizopus nigricans.

In other representative operations,

2,3,5-trichloro-6-(methylsulfonyl)-4-cyanopyridine,3,5-difluoro-4,6-bis(propylthio)-2-cyanopyridine,3,5,6-trifluoro-4-(methylthio)-2-cyanopyridine and 3,5,6trichloro-4-(propylsulfonyl)-2-cyanopyridine each when employed as thesole toxic constituent in liquid compositions in amounts of 5 parts permillion of the ultimate 16 composition, give 100 percent kill andcontrol of yellow fever mosquito larvae. In other operations,

3,5,6-trifluoro-4-(methylthio)-2-cyanopyridine.

2,3 ,5-trichloro-6- (propylsulfonyl -4-cyanopyridine,

3,5, 6-trichloro-4- (methylsulfonyl) -2-cyanopyridine,

3 ,5 ,6-trichloro-4- propylthio -2-cyanopyridine and 2,3,5 trichloro-6-(methylsulfonyl)-4-cyanopyridine each when employed as the sole toxicconstituent in a nutrient solution in amounts of at least 10 parts permillion of the ultimate composition, give substantially complete killand control of Chlorella algae.

In other operations, aqueous compositions containing3,5,6-trichloro-4-mercapto-2-cyanopyridine as the sole toxicant at aconcentration of 500 parts per million give complete kills of the commonhousefly; aqueous compositions containing3,5,6-trifluoro-4-(methylthio)-2-cyanopyridine as the sole toxicant at aconcentration of 300 parts per million by weight give complete kills ofRound worm larvae and aqueous compositions containing 3,5,6-trichloro-4-(methylsulfonyl)-2-carboxypyridine as the sole toxicant at aconcentration of 500 parts per million by weight give substantial killand control of American cockroach.

In another operation, aqueous compositions containing one of2,3,5-trichloro-6-(methylsulfonyl)-4-cyanopyridine,3,5,6-trichloro-4-(methylsulfonyl)-2-cyanopyridine,2,5,6-trichloro-4-(methylsulfinyl)-3-cyanopyridine,3,5,6-trifluoro-4-(methylthio)-2-cyanopyridine and3,5,6-trichloro-4-(propylsulfonyl)-2-cyanopyridine as the sole toxicantgive substantially complete kills of Elodea, Cabomba and Moneywort whenemployed at a concentration of 10 parts per million by weight of theultimate composition.

In another representative operation, 2,3,5-trichloro-6-(methylsulfonyl)-4-cyanopyridine when dispersed in a commercial latexpaint composition as the sole toxicant and in an amount of 1.0 percentby weight of the ultimate paint composition and the paint applied towood panels which are dried and thereafter exposed for two months in atropical chamber at a relative humidity of percent and a temperature of82 F. completely prevented any mold or mildew growth.

PREPAMTION OF STARTING MATERIALS The polyhalo-, monoand dicyanopyridinesemployed as starting materials can be prepared by the method of US. Pat.3,325,503 wherein cyano-substituted pyridines are chlorinated withchlorine gas in vapor phase operations employing a carbon catalystactivated with barium chloride at a temperature of about 300400 C. Thepolyhalo, monoor dicyanopyridine may then be converted to the bromo orfluoro or partial bromo or fluoro cyanopyridine counterparts employingknown techniques of halide exchange, wherein the above-identifiedtetrachlorocyanopyridines and trichlorodicyanopyridines are treated withgaseous hydrogen bromide in an acid medium or potassium fluoride in apolar solvent and conveniently at the boiling temperature and underreflux.

Following the exchange, the desired product is separated by conventionalprocedures such as washing with water, extraction and fractionaldistillation.

The cyano-substituted pyridines employed to prepare the polyhalo-,monoor dicyanopyridines are commercially available and may be preparedby the ammoxidation of methylpyridine as described in ChemicalEngineering Progress, September 1964, pp. 48-49.

The pol'yhalomonoand dicarbamoylor carboxypyridines starting materialscan be prepared by conventionally controlled hydrolysis of theappropriate polyhalomonoor dicyanopyridines with either an acid or baseor with alkaline hydrogen peroxide.

1 7 What is claimed is: 1. A compound corresponding to the formulawherein R represents hydrogen, alkyl of 1 to 12 carbon atoms,mono(chloro-, fluoroor bromo-)alkyl of l to 12 carbon atoms, alkenyl of2 to 10 carbon atoms, mono- (chloro-, fluoroor bromo)alkenyl of 2 to 10carbon atoms, cycloalkyl of 3 to 6 carbon atoms, mono (chloro-, fluoroorbromo-)cycloalkyl of 3 to 6 carbon atoms, phenyl, aral'kyl of 7 to 9carbon atoms, alkaryl of 7 to 9 carbon atoms or mono(chloro-, fluoroorbromo-) phenyl; Q represents sulfide (-S), sulfinyl each X independentlyrepresents chlorine, bromine or fluorine; n represents an integer of 0to 3, inclusive; m represents an integer of 1 to 3, inclusive, prepresents an integer of 1 and the sum of n+m+p equals an integer of 2to 5, inclusive, with the provisos that when Q or sulfonyl Cl-' N 7. Thecompound of claim 4 wherein R is methyl.

References Cited UNITED STATES PATENTS 3,519,634 7/1970 Mohr et al.260-294.8 G

ALAN L. RO'I MA'N, Primary Examiner U.S. Cl. X.R.

27-11; l17-l38.5; 252-380; 260-294.8 G; 270 R; 424-263, 66.

